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88 The PCB Magazine • February 2016
is a reaction." As applied to RCA it means that
an action in one area triggers an action in an-
other, and another, and so on. By tracing back
these actions, you can discover where the prob-
lem started and how it manifested into the
symptom you're now facing.
You'll usually find three basic types of
causes:
1. Physical causes: Tangible, material items
failed in some way (e.g., a plating rectifier
stopped working).
2. Human causes: People did something
wrong, or did not do something that was
needed. Human causes typically lead to
physical causes (e.g., no one performed
PM on the rectifier, which led to it
failing).
3. System causes: A system, process, or
policy that people use to make decisions
or do their work is faulty (e.g., the rectifier
was not included in the PM system).
(Remember my earlier statement that 95%
of causes would be directly attributable to
a management or system issue?)
RCA considers all three types of causes and
involves investigating the patterns and trends
of negative effects, finding hidden flaws in the
system, and discovering specific actions that
contributed to the problem. This often means
that RCA reveals more than one root cause,
each of which needs to be thoroughly vetted
through the process.
While there may be the occasional Nero
Wolfe in a company (or for my younger read-
ers, a Gil Grissom), advanced RCA skills are gen-
erally a learned behavior. The first investment
should be in advanced problem-solving train-
ing for (at a minimum) all management on the
tools discussed earlier in this column. I like to
make the analogy to one of my favorite televi-
sion programs, Crime Scene Investigation (the
Grissom reference). A quality professional is like
a crime scene investigator, and the defect is the
crime scene. As illustrated in Figure 2, and dur-
ing each episode of CSI, the point is reiterated
that the evidence will lead to the origin of the
crime. The same is true with root cause analy-
sis; where you find one you will always find the
other.
PCB
Steve Williams is the president of
The Right Approach Consulting llC.
To read past columns, or to contact
Williams, click here.
root Cause analysis: Csi for the pCb industry
The success story of information
processing by way of moving elec-
trons is slowly coming to an end.
The trend towards more and more
compact chips constitutes a major
challenge for manufacturers, since
the increasing miniaturization creates partly unsolv-
able physical problems. This is why magnetic spin
waves could be the future: They are faster than elec-
tronic charge carriers and use less power. Research-
ers at the Helmholtz-Zentrum Dresden-Rossendorf
(HZDR) and TU Dresden have developed a method
for controlling the propagation of these information
carriers at the nanolevel in a targeted and simple way;
so far,
this required a lot of power. They have thus cre-
ated a basis for nanocircuits that use spin waves.
"our
current information pro-
cessing is based on electrons,"
explains
Dr. Helmut Schultheiß
from the HZDR's Institute of Ion
Beam Physics and Materials Re-
search. "These charged particles
flow through the wires, creating electric currents. Yet
in the process they collide with atoms and lose energy,
which escapes into the crystal lattice in the form of
heat. This means that chips get all the warmer, the
closer the elements on them are grouped together.
Eventually they fail, because the heat cannot be con-
veyed anymore." This is why Schultheiß, head of an
Emmy
noether Junior Research Group, pursues a dif-
ferent approach: information transport via spin waves
(magnons).
A Highway for Spin Waves